The present invention relates to knitted fabrics, particularly fabrics knitted on fine gauge knitting machines and therefore suitable for use in apparel such as hosiery and undergarments. Fabrics according to the present invention are capable of being manufactured on machines described in applicant""s prior U.S. Pat. Nos. 6,085,554; 6,089,045; 6,170,299; 6,230,523; and 6,321,578. More particularly, the invention relates to a fabric wherein a loop is transferred from a selected needle to an adjacent needle by enlarging the loop on the selected needle and then inserting the other needle through the enlarged loop before the selected needle releases the loop. The term loop is used below to define the segment of yarn being manipulated by the needles, but the term xe2x80x9cstitchxe2x80x9d can be used interchangeably.
Circular knitting machines knit together multiple strands of yarn into a tubular fabric, hosiery blank or other structure. The hosiery blank is then finished according to conventional processes to create finished hosiery articles, such as socks, hose and stockings, or other garments such as shirts, shorts, and undergarments such as brassieres and panties. Such machines include a plurality of needles positioned in axial slots formed in an exterior surface of a rotatable needle cylinder. Each needle includes a shank having opposed ends. A hook is formed in a top end of the needle shank and a butt is formed in the bottom end of the needle shank. A plurality of sinkers are mounted in a sinker ring positioned on a top end of the needle cylinder such that the sinkers are alternately positioned between the needles. Circular knitting machines also include a feeder mechanism that delivers yarn onto the passing needles. The yarn forms a loop or loop around each needle.
Apparel with decorative patterns formed by open-work in the fabric created by transferred knitting loops is old and conventional. The space not occupied by the transferred loop creates a hole in the fabric, and the pattern of holes in the fabric collectively create the desired decorative effect. Heretofore such designs have been limited to relatively coarse gauge fabrics due to the difficulty in transferring very small loops between fine gauge needles. Thus, there is a need for a knitting machine and method which permits the creation of decorative open-work patterns in fine gauge knitted fabric, including fine gauge fashion hosiery, such as tights, pantyhose and similar articles.
For example, U.S. Pat. No. 3,838,583 to Rumi et al. discloses apparatus which modifies a circular knitting machine so that it can create openings with transfer loops. The Rumi apparatus includes a dial plate eccentrically positioned over and internal to a needle cylinder and a planetary gear eccentrically positioned over and external to the needle cylinder. The upper surface of the dial plate is provided with a plurality of internal punches slidable in a radial direction, and the upper surface of the planetary gear is provided with a plurality of external punches slidable in a radial direction. The internal punches are inclined suitably in the direction opposite of the direction of rotation. Devices are provided to control the axial movement of the internal and external punches and cam means are provided to raise the needles to the level of the punches. Finally, a plurality of movable sinkers are positioned on the needle cylinder and each partially surround one of the needles. The strands of yarn loop around the needles and extend over the sinkers.
In operation, the selectors raise a specified needle or group of needles past their normal working position. The loop on the needle catches on a needle shoulder which raises the loop above the sinker surrounding the needle. The sinker, which has an end hook, then advances and its hook enters the loop causing the loop to enlarge. Immediately afterwards, either of the two punches enter the loop by passing adjacent to an undercut in the needle. The needle is then returned to its normal position leaving the loop on the punch. The punch transports the loop to the intended needle which is raised up through the loop. That needle continues to rise until the loop is removed from the punch and then returns to its normal position. If the internal punch is used, the loop is transferred to the needle preceding the needle from which the loop was taken. If the external punch is used, the loop is transferred to the needle following the needle from which the loop was taken.
The Rumi apparatus, like other existing apparatus used for transferring loops, first removes the loop from the selected needle and then transfers that loop to the following needle. This practice can only be used effectively on circular knitting machines operating with one hundred and twenty (120) needles or less because the small size of the needles and loops on most circular knitting machines operating more than one hundred and twenty (120) needles prevents the apparatus from reliably transferring the loop. A missed transfer creates a defect which results in a less than first-quality product. The missed transfer problem is naturally exacerbated when the diameter of the needle cylinder is decreased and/or the number of needles being operated is increased.
Consequently, transfer loops cannot be reliably made on prior art fine gauge circular knitting machines. A need, therefore, exists for a method and apparatus for effectively transferring loops from a selected needle to an adjacent needle without dropping a loop and without creating other defects in hosiery articles manufactured on a circular knitting machine capable of creating fine gauge articles.
Therefore, it is an object of the invention to provide a fabric having a pattern of small openings which collectively create a decorative appearance to the fabric. Unlike existing methods and apparatus, the present invention enables open-work patterns to be formed in very fine gauge hosiery created on, for example, circular knitting machines operating 120 or more needles positioned on a needle cylinder having a diameter of 3.5 inches or less. The invention is capable of being used on any gauge machine with as little as 1 mm spacing between needles.
Accordingly, a principal object of the present invention is to provide a method for virtually error-free transfer of a loop from a selected needle to a following needle on a circular or tubular knitting machine, including but not limited to a fine gauge circular or tubular hosiery knitting machine, such as one having 120 or more needles positioned on a needle cylinder having a diameter of 3.5 inches or less.
A further object of the invention is to provide a knitted fabric wherein the transferred loops are formed in a regularly spaced, non-representational array to define ventilation openings.
It is another object of the invention to provide garments fabricated from a knitted fabric having openings formed by transferred loops formed in a regularly spaced, non-representational array to define ventilation openings.
It is another object of the invention to provide garments fabricated from a knitted fabric having openings formed into a decorative pattern of openings representative of an object.
It is another object of the invention to provide a fabric and garments fabricated from the fabric wherein either regularly spaced or decorative patterns of openings are formed on in a fabric structure which is otherwise sufficiently dense to provide solid, non-see-through background which accentuates the appearance of the openings and provides a more distinct pattern.
These and other objects of the present invention are achieved in the preferred embodiments disclosed below by providing an openwork tubular knitted fabric, comprising closely knitted, fine gauge yarns formed into knitted loops utilizing at least 11 needles per inch and having at least 25 courses per inch. The fabric is formed according to the steps of providing a tubular knitting machine having a plurality of needles mounted in axial needle slots in a needle cylinder at a spacing of at least 11 needles per inch, each of said needles having a hook formed in a top end of a needle shank and a latch pivotally mounted on the needle shank below the hook for opening and closing the hook, and including a deflector for deflecting a loop of yarn being formed by a needle into the vertical plane of an adjacent needle, and a needle cam mounted for reciprocal movement between first and second vertically-spaced positions. In the first position the needle cam lowers successive needles to a position where the loop of yarn is released from a selected loop-forming needle and transferred to a transfer needle. In the second position the needle cam lowers successive needles to a position where the loop of yarn is transferred to a transfer needle adjacent the selected loop forming needle without being released from the selected loop-forming needle to thereby form a no-run stitch in the knitted fabric. A needle is selected from which a loop is to be transferred and the loop is enlarged on the selected needle by deflecting the loop out of the vertical plane of the selected needle laterally into the vertical plane of an adjacent needle while the adjacent needle is in a lowered, non-interfering position relative to the deflected loop. The adjacent needle is moved upwardly into the enlarged loop. When the needle cam is in the first position, the selected needle is removed from the deflected loop, whereby the loop is transferred to the adjacent needle thus creating an opening in the fabric. When the needle cam is in the second position, the deflected loop is retained on the selected needle while the loop is also transferred to the adjacent needle thus creating an opening in the fabric.
According to one preferred embodiment of the invention, the fabric includes a plurality of the openings in the fabric formed in accordance with a predetermined pattern.
According to another preferred embodiment of the invention, the fabric has a diameter during formation of between 2.5 inches and 36 inches.
According to another preferred embodiment of the invention, the fabric is knitted with a stitch selected from the group consisting of plain stitch rib stitch, no-run stitch, float stitch, pineapple stitch, and plating stitch.
According to yet another preferred embodiment of the invention, the fabric is constructed of yarns selected from the group consisting of cotton, nylon, stretch nylon, acrylic, and polypropylene.
According to yet another preferred embodiment of the invention, the fabric is comprised of a blended yarn containing cotton and stretch nylon.
According to yet another preferred embodiment of the invention, the fabric in constructed on a machine having approximately 17 needles per inch and 30 courses per inch.
According to yet another preferred embodiment of the invention, the cotton yarn is a 40 denier singles yarn and the stretch nylon yarn is a 70 denier singles yarn.
According to yet another preferred embodiment of the invention, the fabric is comprised of stretch nylon.
According to yet another preferred embodiment of the invention, the fabric in constructed on a machine having approximately 17 needles per inch and 40 courses per inch.
According to yet another preferred embodiment of the invention, the stretch nylon yarn is a 30/2 denier plied yarn.
According to yet another preferred embodiment of the invention, the fabric is constructed on a machine having approximately 17 needles per inch and 35 courses per inch.
According to yet another preferred embodiment of the invention, the stretch nylon yarn is a 50/2 denier plied yarn.
According to yet another preferred embodiment of the invention, the fabric is constructed on a machine having approximately 25 needles per inch and 60 courses per inch.
According to yet another preferred embodiment of the invention, the yarn is a 15/2 denier plied yarn.
According to yet another preferred embodiment of the invention, the fabric is constructed on a machine having approximately 30 needles per inch and 70 courses per inch.
According to yet another preferred embodiment of the invention, the yarn is a 15 denier singles yarn.
According to yet another preferred embodiment of the invention, an openwork tubular knitted fabric is provided, comprising closely knitted, fine gauge yarns formed into knitted loops utilizing at least 11 needles per inch and having at least 25 courses per inch, wherein the fabric is characterized by a dense ground of loops sufficiently closed to prevent showthrough. A predetermined pattern of holes is defined by transferred stitches in the fabric formed according to the steps of providing a tubular knitting machine having a plurality of needles mounted in axial needle slots in a needle cylinder at a spacing of at least 11 needles per inch, each of said needles having a hook formed in a top end of a needle shank and a latch pivotally mounted on the needle shank below the hook for opening and closing the hook, and including a deflector for deflecting a loop of yarn being formed by a needle into the vertical plane of an adjacent needle, and a needle cam mounted for reciprocal movement between first and second vertically-spaced positions. In the first position the needle cam lowers successive needles to a position where the loop of yarn is released from a selected loop-forming needle and transferred to a transfer needle. In the second position the needle cam lowers successive needles to a position where the loop of yarn is transferred to a transfer needle adjacent the selected loop forming needle without being released from the selected loop-forming needle to thereby form a no-run stitch in the knitted fabric. A needle is selected from which a loop is to be transferred. The loop is enlarged on the selected needle by deflecting the loop out of the vertical plane of the selected needle laterally into the vertical plane of an adjacent needle while the adjacent needle is in a lowered, non-interfering position relative to the deflected loop. The adjacent needle is moved upwardly into the enlarged loop. When the needle cam is in the first position, the selected needle is removed from the deflected loop, whereby the loop is transferred to the adjacent needle thus creating an opening in the fabric. When the needle cam is in the second position, the deflected loop is retained on the selected needle while the loop is also transferred to the adjacent needle thus creating a no-run opening in the fabric.
According to yet another preferred embodiment of the invention, the fabric is formed into a garment selected from the group consisting of hosiery, shirts, panties, shorts and brassieres.
According to yet another preferred embodiment of the invention, the predetermined pattern is a regularly-spaced array of ventilation openings.
According to yet another preferred embodiment of the invention, the predetermined pattern is a decorative pattern of openings representative of an object.